If your recording sounds fine for the first few minutes and then slowly falls out of sync with your video — or starts sounding subtly warped, like it’s speeding up or slowing down — the cause is almost always a sample rate mismatch, not a bad microphone or a bad take.
What a sample rate actually is
Every digital audio signal is made of thousands of tiny snapshots per second. The sample rate is how many of those snapshots are taken each second — commonly 44,100 Hz (44.1kHz) or 48,000 Hz (48kHz). Neither number is “wrong” on its own. The problem starts when two parts of your setup disagree about which one to use.
Where the mismatch comes from
This almost always happens between two settings configured at different times, by different people, for different reasons: your operating system’s default audio device (often 44.1kHz) and your streaming software’s audio setting (often 48kHz, the broadcast standard). When these disagree, your capture software constantly stretches or compresses the incoming audio. Over a short clip this is barely noticeable; over a 45-minute podcast, the drift accumulates until it’s audibly out of step with the picture.
How to check it yourself
Windows: Right-click the speaker icon → Sounds → Playback tab → select your device → Properties → Advanced tab, and note the sample rate. macOS: Open Audio MIDI Setup and check the sample rate for your input device. OBS: Settings → Audio → Sample Rate. Compare the values.
How to fix it
Set both to 48kHz, the broadcast and streaming industry standard. Change your OS-level device sample rate, confirm OBS matches, and do a short test recording to verify the drift is gone.
The broader lesson
This is a good example of a class of streaming problems that are invisible in isolation, and only become obvious when you check how two settings relate to each other.